JP6357271B1 - Columnar conductor structure - Google Patents

Abstract

A columnar conductor structure having excellent shielding properties, electrical conductivity, and heat resistance is provided.
A columnar conductor structure A in which a through hole 102 provided in a thickness direction of a substrate 100 is filled with a conductor, and the columnar conductor structure A includes a first layer 103 in contact with a wall surface or a bottom surface of the through hole 102, and The first layer 103 is a metal layer having a thickness of 0.1 μm to 10 μm, and a second layer 104 provided on the surface thereof and a filling layer 105 filling the through hole 102 inside the second layer 104. The second layer 104 is composed of a layer containing a first intermetallic compound having a thickness of 1 μm to 10 μm, and the filling layer 105 is composed of a second intermetallic compound 1051 and an alloy 1052, and the second intermetallic compound 1051. Occupies at least 5 mass% in the filled layer 105, and the second intermetallic compound 1051 is dispersed in the alloy 1052.
[Selection] Figure 1

Description

  The present invention relates to a columnar conductor structure.

  For example, in a semiconductor device, until now, a method has been adopted in which semiconductor chips are arranged in a plane on a substrate and connected between them by wiring. However, with this method, the mounting area increases with the number of semiconductor chips, and the wiring length also increases. Therefore, it is difficult to realize a small, large capacity, high performance and low power consumption of the semiconductor device. is there. Under the present circumstances where the miniaturization technology has advanced to the limit, it has reached the limit to realize large capacity, high performance and low power consumption through miniaturization and miniaturization of semiconductor chips.

  Therefore, development of a semiconductor device having a three-dimensional arrangement according to a so-called TGV (Through Glass Via) system in which semiconductor chips are stacked and the chips are connected by through electrodes is underway. With TGV technology, a large amount of functions can be packed in a small footprint, and important electrical paths between elements can be dramatically shortened, leading to faster processing.

  Typical techniques for realizing a three-dimensionally arranged semiconductor device according to the TGV method are a plating method in which a through electrode is formed by applying a plating technique, and a vacuum chamber in which a silicon substrate having a fine space is reduced to a vacuum pressure. After the silicon substrate reaches almost the same temperature as the molten metal, the inside of the vacuum chamber is pressurized to, for example, atmospheric pressure or higher, and the molten metal is filled into a fine space, cured, and melted. A molten metal filling method for forming a through conductor made of a solidified conductor.

  However, it is extremely difficult to sufficiently fill the bottom of the fine space having a high aspect ratio without causing voids or deformation after curing. As a prior art capable of overcoming such technical difficulties, a filling method and apparatus described in Patent Documents 1 and 2 are known.

  The technique described in Patent Document 1 is a method of filling and hardening a molten metal in a minute space existing on a wafer, and applying a forced external force exceeding atmospheric pressure to the molten metal in the minute space. And a step of cooling and hardening the molten metal. The forced external force is given by at least one selected from a pressing pressure, an injection pressure, or a rolling pressure, and the molten metal is opened from the opening surface side of the fine space with the other end side of the fine space closed. To be applied. Patent Document 2 discloses an apparatus for performing the method described in Patent Document 1.

  According to the techniques described in Patent Documents 1 and 2 described above, the hard space can be filled with a filler without generating voids or voids in the conductor structure in the fine space, and the hardened metal cooled in the fine gap. It is possible to obtain excellent operational effects such as avoiding the formation of concave surfaces and contributing to simplification of the process and improvement of yield.

  The inventions disclosed in Patent Documents 1 and 2 are extremely useful technologies for the practical application of TGV (through Glass via) technology, but for the recent application of power semiconductors, etc., further shielding properties and electrical conductivity of the conductor structure Improvement in heat resistance is required.

  Patent Document 3 discloses a method of forming a silicon through wire (TSV) in a through hole of a silicon board in a three-dimensional integration technique, and a space inside a through hole having a small diameter prepared in the silicon board. Discloses a technique of filling a molten solder with molten solder. Specifically, a manufacturing method is disclosed in which, after introducing Cu powder into a through-hole, Sn powder is heated and melted. However, in the technique disclosed in Patent Document 3, Cu and Sn react at the entrance of the through hole, an intermetallic compound is generated instantaneously, and a conductor structure cannot be formed inside the through hole. was there.

Japanese Patent No. 4278007 Japanese Patent No. 4505540 Japanese Patent No. 6021125

  The subject of this invention is providing the columnar conductor structure excellent in shielding property, electroconductivity, and heat resistance.

As a result of intensive studies, the present inventor has found that the above problem can be solved by specifying the fine structure of the filling layer filling the inside of the bottomed hole or the through hole.
That is, the present invention is as follows.

1. A columnar conductor structure in which a conductor is filled in a bottomed hole or a through hole provided in the thickness direction of the substrate,
The columnar conductor structure includes a first layer in contact with a wall surface or a bottom surface of the bottomed hole or the through hole, a second layer provided on a surface of the first layer, and the bottomed inner side of the second layer. A hole or a filling layer filling the through hole,
The first layer is a metal layer having a thickness of 0.1 μm to 10 μm,
The second layer includes a layer containing a first intermetallic compound having a thickness of 1 μm to 10 μm,
The packed bed is made of a second intermetallic compound and an alloy,
The second intermetallic compound occupies at least 5% by mass in the packed bed, and the second intermetallic compound is dispersed in the alloy.
Columnar conductor structure.
2. The columnar conductor structure described in 1 above,
The first layer includes a metal capable of forming an intermetallic compound with Sn,
The first intermetallic compound in the second layer is composed of an intermetallic compound of Sn and the metal of the first layer,
The filling layer includes Sn or an Sn alloy,
Columnar conductor structure.
3. The columnar conductor structure described in 1 or 2 above,
The substrate is an insulating substrate;
Columnar conductor structure.
4). The columnar conductor structure described in 1 or 2 above,
The substrate is a semiconductor substrate;
An insulating layer exists between the bottomed hole or the wall surface or bottom surface of the through hole and the first layer.
Columnar conductor structure.
5. The semiconductor device which has the columnar conductor structure in any one of said 1-4.

  The columnar conductor structure of the present invention includes a first layer in contact with a wall surface or a bottom surface of a bottomed hole or a through hole provided in a thickness direction of the substrate, a second layer provided on a surface of the first layer, A filling layer filling the bottomed hole or the through-hole inside two layers, the thicknesses of the first layer and the second layer are set within a specific range, and the filling layer is formed of an intermetallic compound. Since the amount and form of the intermetallic compound are specified, it is possible to provide a columnar conductor structure excellent in shielding properties, conductivity, and heat resistance.

It is a schematic sectional drawing for demonstrating the columnar conductor structure of this invention. It is a figure for demonstrating an example of the manufacturing apparatus suitable for manufacture of the metal particle of this invention. It is a cross-sectional STEM-EDS Mapping SEM image of the metal particle of this invention obtained in the Example. It is a SEM image of the section of the columnar conductor structure of the present invention created in the example. 4 is a SEM image of a cross section of a columnar conductor structure created in Reference Example 1. 6 is a SEM image of a cross section of a columnar conductor structure created in Reference Example 2.

Hereinafter, the present invention will be further described with reference to the drawings, but the present invention is not limited to the following examples.
FIG. 1 is a schematic cross-sectional view for explaining a columnar conductor structure of the present invention.

  In FIG. 1, a columnar conductor structure A of the present invention is a structure in which a conductor is filled in a bottomed hole or a through hole 102 provided in the thickness direction of an insulating substrate 100, for example (FIG. 1 shows a through hole). ) The hole diameter of the through hole 102 is, for example, 80 μm or less, specifically about 20 μm to 60 μm, and the depth is a value at which the aspect ratio to the hole diameter is 1 or more, preferably 5 or more. When the substrate 100 is, for example, a glass substrate, a large number of through holes 12 are provided in the glass surface.

  The columnar conductor structure A fills the through-hole 102 inside the first layer 103 in contact with the wall surface or bottom surface of the through-hole 102, the second layer 104 provided on the surface of the first layer 103, and the second layer 104. And a filling layer 105.

  The first layer 103 is a metal layer having a thickness of 0.1 μm to 10 μm. For example, a layer made of a metal capable of forming an intermetallic compound with Sn is preferable. Cu is suitable as the metal. The first layer can be provided, for example, with Cu on the surface of the through-hole 12 using a technique such as plating or sputtering.

  The second layer 104 includes a layer including a first intermetallic compound having a thickness of 1 μm to 10 μm. The first intermetallic compound may include a low melting point metal and a high melting point metal. For example, Ag, Cu , Au, Pt, Ti, Zn, Al, Fe, Si, and Ni.

The filling layer 105 includes a second intermetallic compound 1051 and an alloy 1052. The second intermetallic compound 1051 can include a low melting point metal and a high melting point metal, and is selected from the group of Ag, Cu, Au, Pt, Ti, Zn, Al, Fe, Si, and Ni, for example. It can be configured by material. The second intermetallic compound 1051 occupies at least 5 mass% in the packed bed 105, and the second intermetallic compound 1051 is dispersed in the alloy 1052. According to a preferred embodiment of the present invention, at least a part of the second intermetallic compound 1051 is bonded to the second layer 104, and the second intermetallic compound 1051A is bonded to each other. The skeletal structure is constructed so as to cross between. According to such a structure, the conductivity and heat resistance of the columnar conductor structure A can be further increased.
In addition, the second intermetallic compound 1051 can suppress volume shrinkage during cooling, grain growth of the conductor, and crystal growth. Therefore, generation of microcracks in the columnar conductor structure A can be suppressed.

  The alloy 1052 of the filling layer 105 can be made of a low melting point metal or alloy, and contributes to the shielding performance of the columnar conductor structure A.

  The columnar conductor structure A of the present invention as described above can be formed using the metal particles described below (hereinafter sometimes referred to as the metal particles of the present invention). In addition, although the metal particle of this invention demonstrated below consists of Sn and Cu, this invention is not restrict | limited to this form. The second layer 104 and the filling layer 105 can include a low melting point metal and a high melting point metal, for example, selected from the group of Ag, Cu, Au, Pt, Ti, Zn, Al, Fe, Si and Ni As described above, it can be constituted by the prepared material.

  The metal particle of this invention can be manufactured from the raw material (henceforth 8Cu * 92Sn) which combined 8 mass% Cu and 92 mass% Sn, for example. For example, by melting 8Cu · 92Sn and supplying it onto a dish-shaped disk that rotates at high speed in a nitrogen gas atmosphere, the molten metal is scattered as small droplets by centrifugal force, and cooled and solidified under reduced pressure. The metal particles of the invention can be obtained. In addition, in the said form, the metal particle of this invention does not exclude inclusion of other elements other than Cu and Sn.

  An example of a production apparatus suitable for producing the metal particles of the present invention will be described with reference to FIG. The granulation chamber 1 has a cylindrical shape at the top and a cone shape at the bottom, and has a lid 2 at the top. A nozzle 3 is inserted vertically in the center of the lid 2, and a dish-shaped rotating disk 4 is provided immediately below the nozzle 3. Reference numeral 5 denotes a mechanism for supporting the dish-shaped rotating disk 4 so as to be movable up and down. The generated particle discharge pipe 6 is connected to the lower end of the cone portion of the granulating chamber 1. The upper part of the nozzle 3 is connected to an electric furnace (high frequency furnace) 7 for melting the metal to be granulated. The atmospheric gas adjusted to a predetermined component in the mixed gas tank 8 is supplied to the inside of the granulating chamber 1 and the upper part of the electric furnace 7 through the pipe 9 and the pipe 10, respectively. The pressure in the granulating chamber 1 is controlled by the valve 11 and the exhaust device 12, and the pressure in the electric furnace 7 is controlled by the valve 13 and the exhaust device 14, respectively. The molten metal supplied from the nozzle 3 onto the dish-shaped rotating disk 4 is scattered in the form of fine droplets by the centrifugal force of the dish-shaped rotating disk 4, and is cooled under reduced pressure to become solid particles. The generated solid particles are supplied from the discharge pipe 6 to the automatic filter 15 and separated. Reference numeral 16 denotes a fine particle collecting apparatus.

The process of cooling and solidifying the molten metal under reduced pressure is important for forming the crystal structure of the metal particles of the present invention.
For example, the following conditions can be mentioned.
Dish-shaped rotating disk 4: A dish-shaped disk having an inner diameter of 60 mm and a depth of 3 mm is used, and the speed is 80,000 to 100,000 rpm.
Granulation chamber 1: After depressurization using a vacuum tank having the ability to depressurize to about 9 × 10 ⁻² Pa, exhausting simultaneously while supplying nitrogen gas at 15 to 50 ° C., granulation chamber 1 The atmospheric pressure is set to 1 × 10 ⁻¹ Pa or less.
The particle size of the metal particles produced under these conditions is, for example, 20 μm or less in diameter, and typically 2 μm to 15 μm.

  The produced metal particles of the present invention can be processed into a sheet or paste. The sheet | seat which consists of a metal particle of this invention can be obtained by supplying the said metal particle between a pair of press-contacting rollers rotated in the direction which opposes, for example, and press-contacting. The paste made of the metal particles of the present invention can be obtained by mixing the metal particles of the present invention in an organic vehicle. In addition, in the range which does not impair the effect of this invention, it is good also as a mixture with a metal particle by adding other particle | grains, such as SnAgCu type-alloy particle | grains and / or Cu particle | grains, to the said sheet | seat or the said electrically conductive paste. These other particles may be coated with a metal such as Si as required.

  The form which produces the columnar conductor structure A of this invention using the metal particle of this invention manufactured as mentioned above is demonstrated. The columnar conductor structure A of the present invention can be produced, for example, according to the method described in Japanese Patent No. 5450780.

First, for example, Cu is provided on the surface of the through hole 102 of the insulating substrate 100 so as to have a thickness of 0.1 μm to 10 μm using a known method such as plating or sputtering.
Subsequently, the metal particles of the present invention are placed on the through-hole 102, and are pressurized and cured while being heated to 230 ° C to 280 ° C in a reducing atmosphere. In such a process, the metal particles of the present invention are melted by heating, enter into the through hole 102, react with Cu as the first layer, and contain the first intermetallic compound (for example, containing Cu ₃ Sn) The second layer is formed with a thickness ranging from 1 μm to 10 μm. At the same time, the filling layer 105 is formed with the same structure as that of the metal particles of the present invention. The metal particles of the present invention are particles in which an intermetallic compound crystal containing Sn and Cu (for example, containing Cu ₆ Sn ₅ ) is composed of a crystal containing a nano-sized intermetallic compound in an Sn alloy. During the formation of the metal particles, an intermetallic compound is precipitated in the Sn alloy, and the deposited intermetallic compound is filled in the through-hole together with the molten alloy without being melted. It can be further increased.

  As a reducing agent for forming a reducing atmosphere, it is preferable to use vapor of carboxylic acid (R—COOH, R is a monovalent functional group). Examples of carboxylic acids include formic acid, acetic acid, acrylic acid, propionic acid, butyric acid, caproic acid, succinic acid, succinic acid, salicylic acid, malonic acid, enanthic acid, caprylic acid, pelargonic acid, lactic acid, and capric acid. One of them may be selected, or a plurality may be selected and mixed. Among these carboxylic acids, formic acid is suitable. Since the reducing action by carboxylic acid is generally significant at a temperature exceeding its boiling point, for example, 200 ° C. or higher, it is preferable that the reducing atmosphere satisfy this temperature range.

  Further, when heating the metal particles of the present invention, it is preferable that the inside of the chamber is in a reduced pressure atmosphere. After the decompression process, a differential pressure filling method in which the internal pressure of the chamber is increased may be employed. By such means, the metal particles of the present invention can be reliably filled into the through hole 102. Further, at the time of heating, if the insulating substrate 100 is vibrated by ultrasonic waves or the like, the filling operation can be performed smoothly.

  In the above description, the insulating substrate 100 is taken as an example of the substrate. However, the substrate used in the present invention is a fine through-hole such as a wafer, a circuit substrate, a laminated substrate, a semiconductor substrate, or a MEMS (Micro-Electro-Mechanical Systems). Those having 102 are widely included. Specifically, a through hole represented by TGV (Through Glas Via), a non-through hole (blind hole), and the like. In particular, as the substrate in the present invention, a semiconductor substrate is suitable, and the columnar conductor structure of the present invention includes a form in which an insulating layer exists between the wall surface or bottom surface of the bottomed hole or through hole and the first layer, Thus, it is useful to employ the columnar conductor structure of the present invention as a semiconductor device.

  EXAMPLES Hereinafter, although an Example and a comparative example further demonstrate this invention, this invention is not restrict | limited to the following example.

Example 1
Using 8Cu · 92Sn as a raw material, metal particles having a diameter of about 3 to 13 μm were manufactured using the manufacturing apparatus shown in FIG.
At that time, the following conditions were adopted.
Dish-shaped rotating disk 4: A dish-shaped disk having an inner diameter of 60 mm and a depth of 3 mm was used, and the speed was 80,000 to 100,000 rpm.
Granulation chamber 1: After depressurization using a vacuum tank having the ability to depressurize to about 9 × 10 ⁻² Pa, exhausting simultaneously while supplying nitrogen gas at 15 to 50 ° C., granulation chamber 1 The internal pressure was set to 1 × 10 ⁻¹ Pa or less.

  FIG. 3 is a cross-sectional STEM-EDS Mapping SEM image of the metal particles of the present invention obtained in the examples. From FIG. 3, it is observed that the metal particles of the present invention contain an intermetallic compound crystal and an Sn alloy.

Subsequently, the columnar conductor structure of the present invention as shown in FIG. 1 was prepared using the obtained metal particles of the present invention.
First, Cu was plated on the surface of the through hole 102 of the insulating substrate 100 by a plating method. Thereby, the first layer 103 made of Cu having a thickness of about 2 μm was formed. The inner diameter of the through hole 102 is about 20 to 60 μm.
Subsequently, the insulating substrate 100 on which the first layer 103 is formed is introduced into a vacuum chamber, and the metal particles of the present invention are placed on the through-hole 102 and heated to 250 ° C. to 280 ° C. in a reducing atmosphere made of formic acid. By heating and melting, the metal particles of the present invention were pressurized at 2 to 8 MPa, the metal particles of the present invention were filled in the through holes 102 and cured, and the second layer 104 and the packed layer 105 were formed.

FIG. 4 is an SEM image of a cross section of the columnar conductor structure of the present invention created in the example.
From FIG. 4, it was recognized that the second layer 104 containing the first intermetallic compound (including Cu ₃ Sn) was formed with a thickness of 1.5 μm. The second layer 104 is formed by a reaction between the molten metal particles of the present invention and Cu as the first layer 103. The filling layer 105 is made of a second intermetallic compound 1051 (an intermetallic compound crystal containing Sn and Cu containing Cu ₆ Sn ₅ ) dispersed in an Sn alloy, and the filling layer 105 includes a dispersed intermetallic compound and It was confirmed that it was composed of an alloy phase. Defects such as microcracks were not observed in the columnar conductor structure, and high shielding properties due to intermetallic compounds were revealed.

  In order to confirm the heat resistance of the columnar conductor structure of the present invention created as described above, it was confirmed by a video that there was no melt expansion change in the shape change after standing at 300 ° C. for 10 minutes. As a result, the high heat resistance of the columnar conductor structure of the present invention was confirmed.

Reference example 1
In Example 1, without using the metal particles of the present invention, after introducing Cu powder into the through-hole 102, the Sn powder was heated and melted, and the above heating step and pressure step were performed, Example 1 was repeated.
FIG. 5 is an SEM image of a cross section of the columnar conductor structure created in Reference Example 1.
From the results of FIG. 5, in Reference Example 1, Cu and Sn react at the entrance of the through hole, and an intermetallic compound is generated instantaneously. Only the Cu powder remains in the through hole, and the conductor is inside the through hole. A structure could not be formed.

Reference example 2
In Example 1, Example 1 was repeated except that the metal particles of the present invention were not used and a commercially available SnAgCu-based bonding material (SAC) was used. However, when an attempt was made to examine the heat resistance of the columnar conductor structure, the SAC melted and ejected as shown in FIG. 6B, and the through holes became almost void after the SAC ejection as shown in FIG. 6A. The sex test could not be performed.

  The present invention has been described in detail with reference to the accompanying drawings. However, the present invention is not limited to these, and various modifications can be made by those skilled in the art based on the basic technical idea and teachings. It is self-evident that you can think of it.

DESCRIPTION OF SYMBOLS 1 Granulation chamber 2 Lid 3 Nozzle 4 Dish-shaped rotating disk 5 Rotating disk support mechanism 6 Particle discharge pipe 7 Electric furnace 8 Mixed gas tank 9 Pipe 10 Pipe 11 Valve 12 Exhaust device 13 Valve 14 Exhaust device 15 Automatic filter 16 Fine particle collection device 100 Insulating substrate 102 Through-hole 103 First layer 104 Second layer 105 Filling layer 1051 Second intermetallic compound 1052 Alloy A Columnar conductor structure

Claims (4)

A columnar conductor structure in which a conductor is filled in a bottomed hole or a through hole provided in the thickness direction of the substrate,
The columnar conductor structure includes a first layer in contact with a wall surface or a bottom surface of the bottomed hole or the through hole, a second layer provided on a surface of the first layer, and the bottomed inner side of the second layer. A hole or a filling layer filling the through hole,
The first layer is a metal layer having a thickness of 0.1 μm to 10 μm,
The second layer includes a layer containing a first intermetallic compound having a thickness of 1 μm to 10 μm,
The filling layer is made of a second intermetallic compound and a Sn alloy,
The second intermetallic compound accounts for at least 5% by mass in the packed bed ,
The first layer includes a metal capable of forming an intermetallic compound with Sn,
The first intermetallic compound in the second layer is composed of an intermetallic compound of Sn and the metal of the first layer,
The second intermetallic compound is made of an intermetallic compound crystal containing Sn and Cu containing Cu ₆ Sn ₅ , and the second intermetallic compound is dispersed in the Sn alloy.
Columnar conductor structure. The columnar conductor structure according to claim 1 ,
The substrate is an insulating substrate;
Columnar conductor structure. The columnar conductor structure according to claim 1 ,
The substrate is a semiconductor substrate;
An insulating layer exists between the bottomed hole or the wall surface or bottom surface of the through hole and the first layer.
Columnar conductor structure. The semiconductor device which has the columnar conductor structure in any one of Claims 1-3 .